Five germacrane- and guaiane-type sesquiterpene lactones, including two previously described taraxinic acid derivatives, were isolated from the roots of Taraxacum officinale, together with benzyl glucoside, dihydroconiferin, syringin and dihydrosyringin. The other three lactones were identified as 11beta, 13-dihydrolactucin, ixerin D and ainslioside. Moreover, the stereochemistry at C-11 in dihydrotaraxinic acid was assigned.